Download 13.5 Plant Growth and Development - Hutchison

13.5 Plant Growth and
Development
Pages 605-612
Walking palm
• The adventitious roots in the shade die and
new roots in the direction of the sun form.
Growth
• Increase in size
Differentiation
• A cell becomes specialized to perform a
particular function.
Apical meristem
• found at the tips of plant’s buds, stems and roots.
• primary growth occurs here
• plant height increases
Lateral meristem
• found at the sides of plant’s buds, stems and
roots.
• causes secondary growth
• increases the width of the plant
Primary Growth
• Apical meristem cells divide and elongate
• Differentiation into epidermal, parenchyma or
vascular cell types.
• Shoot apical meristem becomes stems, leaves
and reproductive organs
• Root apical meristem has three zones:
– Zone of maturation
– Zone of elongation
– Zone of cell division
Secondary growth
• Only in woody species after first year.
• Example: vascular cambium and cork
cambium
Light
• Photoreceptor- a molecule that reacts when
struck by light of a certain intensity and/or
wavelength.
• Some seeds need light to germinate
Example: lettuce
• Some seeds need darkness to germinate
Example: lilly
Photoperiod
• Plants respond to daylength
• Timing of flowers
Example: Spinach- long daylength
Example: Tulip-short daylength
Macronutrients
• Large quantities (more than 1g/kg of dry
mass)
Examples: N, P, K
Carbon
• From carbon dioxide in the air
• Carbon backbone of organic molecules
Hydrogen
• From water
Oxygen
• From the air
Nitrogen
• Nitrates and ammonia
• Proteins, DNA, RNA, chlorophyll
chlorosis
Phosphorus
• From hydrogen phosphite ion
• For DNA, RNA, membranes
Potassium
• From K+ ions
• For activation of enzymes and cellular
transport
Calcium
• From calcium ion
• For cell walls, membrane transport
Sulfur
• From sulfate ion
• For proteins
Magnesium
• From magnesium ion
• For chlorophyll, enzyme activation
Micronutrients
• Nutrients needed less than 100 mg/kg of dry
mass.
• B, Cl, Cu, Fe, Mn, Mo, Ni, Zn
• Used for Chlorophyll synthesis, cell division,
enzyme production
Temperature
• Opening and closing stomata
• Timing of seed germination
• Timing of flowering
Soil
•
•
•
•
Medium to anchor roots
Retains water and nutrients
Air
pH